Nafisah L.,University of Pembangunan Nasional Veteran, Yogyakarta |
Abdul Khannan M.S.,University of Pembangunan Nasional Veteran, Yogyakarta |
Shidiq S.A.,University of Pembangunan Nasional Veteran, Yogyakarta
ARPN Journal of Engineering and Applied Sciences | Year: 2016
In the classical Wilson's economic ordering quantity model, it was assumed that the goods can be held infinitely for future demand. However, in practices, as most items we deal with such goods required considering the factors of short shelf life, then some suppliers tries to reduce their lost by offering incremental quantity discount. This paper will try to combine and modify several basic models of deterministic inventory control to design a model for deteriorating item by considering quantity incremental discount under permissible delay in payments. Heuristic approaches used to solve the models. A numerical example has been solved to illustrate the model. © 2006-2016 Asian Research Publishing Network (ARPN). All rights reserved.
Muttaqin Z.,University of Pembangunan Nasional Veteran, Yogyakarta
IET Conference Publications | Year: 2015
A quick, reliable reservoir characterization using core data must provide both geological and engineering works. The new proposed method of pore geometry-structure relating the hydraulic characterization of pore system can lead to improved reservoir characterization. This study is facilitated with 126 core samples of Well-A. PGS method is based on capillary model equation involving hydraulic parameter: effective hydraulic diameter and mean as geometry parameter and hydraulic conductivity as structure parameter. Plot of (k/ø)0.5 vs k/ø3 based on lithofacies description, each rock type will have distinct line whose slopes no more than 0.5 Then porosity-saturation-permeability correlations are formed to result equation predicting permeability from Well-A calibrated by SCAL data. It's demonstrated that cross-plot of the effective hydraulic diameter against porosity can be used to predict permeability. Permeability data distribution method as a comparison and PGS method were simulated in single Well model. It results 9 rock types which 5 of them have been validated with J-Function curve; the permeability prediction in which PGS method shows high accuracy (R2 = 0.9951); after simulated, PGS contributes RF 13.43% or is higher 5.46% against permeability data distribution method. It could be alternative reservoir characterization when using reliable core data that is beneficial in petroleum industry.
Saptono S.,University of Pembangunan Nasional Veteran, Yogyakarta |
Wiyono B.,University of Pembangunan Nasional Veteran, Yogyakarta |
Dewi A.,University of Pembangunan Nasional Veteran, Yogyakarta
ISRM International Symposium - 8th Asian Rock Mechanics Symposium, ARMS 2014 | Year: 2014
The influence of infilling material on rock samples often becomes a problem in determining the shear strength. In fact, discontinuity such as joint is often encountered in rock mass. The presence of discontinuity will change the behavior of rock mass. This phenomena become worst when the joint filled by infilling material. There many problems in the design and construction due to the presence of filled joint rock. Concerning with the signification the effect of filled joint to its shear strength it is necessary to carry out tests on rock samples. A series of laboratory experimentation is carried out to model the filled joint by using Tuff as a joint block and clay infilling material. In these tests is varying parameters of normal stress, infilling thickness and roughness of joint surface. From the test it is showed that the shear strength of a joint decreased significantly with the presence of infilling material in the aperture of a joint. The effect of asperities has influence 25-50% in shear strength of the thickness of the asperities. In tropical country as Indonesia, it is evident that asperities influence of Tuff on the shear strength in tropical country higher than non tropical country, the reduction of shear strength depends on the thickness of infilling material are cohesion of sample filled 0.25 cm of thickness and sample filled 0.5 cm of thickness decrease 73.63% and 86.91% of natural sample condition. © 2014 by Japanese Committee for Rock Mechanics.
Badri H.M.,National University of Malaysia |
Deros B.M.,National University of Malaysia |
Syahri M.,Islamic University of Indonesia |
Saleh C.,University of Pembangunan Nasional Veteran, Yogyakarta |
Fitria A.,University of Pembangunan Nasional Veteran, Yogyakarta
IOP Conference Series: Materials Science and Engineering | Year: 2016
The learning curve shows the relationship between time and the cumulative number of units produced which using the mathematical description on the performance of workers in performing repetitive works. The problems of this study is level differences in the labors performance before and after the break which affects the company's production scheduling. The study was conducted in the garment industry, which the aims is to predict the company production scheduling using the learning curve and forgetting curve. By implementing the learning curve and forgetting curve, this paper contributes in improving the labors performance that is in line with the increase in maximum output 3 hours productive before the break are 15 unit product with learning curve percentage in the company is 93.24%. Meanwhile, the forgetting curve improving maximum output 3 hours productive after the break are 11 unit product with the percentage of forgetting curve in the company is 92.96%. Then, the obtained 26 units product on the productive hours one working day is used as the basic for production scheduling. © Published under licence by IOP Publishing Ltd.
Khannan M.S.A.,University of Pembangunan Nasional Veteran, Yogyakarta |
Maruf A.,Bandung Institute of Technology |
Wangsaputra R.,Bandung Institute of Technology |
Sutrisno S.,University of Pembangunan Nasional Veteran, Yogyakarta |
Wibawa T.,University of Pembangunan Nasional Veteran, Yogyakarta
IOP Conference Series: Materials Science and Engineering | Year: 2016
Material Handling take as important role in Cellular Manufacturing System (CMS) design. In several study at CMS design material handling was assumed per pieces or with constant lot size. In real industrial practice, lot size may change during rolling period to cope with demand changes. This study develops CMS Model with Dynamic Lot Size Material Handling. Integer Linear Programming is used to solve the problem. Objective function of this model is minimizing total expected cost consisting machinery depreciation cost, operating costs, inter-cell material handling cost, intra-cell material handling cost, machine relocation costs, setup costs, and production planning cost. This model determines optimum cell formation and optimum lot size. Numerical examples are elaborated in the paper to ilustrate the characterictic of the model. © Published under licence by IOP Publishing Ltd.
Setyoningrum T.M.,University of Pembangunan Nasional Veteran, Yogyakarta |
Nur M.M.A.,University of Pembangunan Nasional Veteran, Yogyakarta
Biocatalysis and Agricultural Biotechnology | Year: 2015
Production of phycocyanin from Spirulina platensis by mixotrophic condition was favored due to high growth rate result. The objective of this research was to obtain the statistical interaction models of molasses and urea to crude phycocyanin (CPC) production by applying response surface methology (RSM)associated central composite design approach. S. platensis was cultivated under mixotrophic condition by adding varied molasses and urea under continous illumination at 45.5μmolm-2 s-1 for 6 days. By using 2nd order statistical models, optimum phycocyanin production was recorded on 114.74mgL-1 and 0.196L-1 of urea and molasses, respectively. Molasses could be the promising substrate for phycocyanin production of the microalgae. © 2015 Elsevier Ltd.
Muafi,University of Pembangunan Nasional Veteran, Yogyakarta
Journal of Industrial Engineering and Management | Year: 2015
Purpose: This study aims at analyzing the role of empowerment of Green Information Technology (IT) in Small Medium Entreprises (SMEs) and social capital of the creativity and innovation of creative SMEs in Bantul, Yogyakarta, Indonesia. Design/methodology/approach: A statistical technique used in the present study was Partial Least Square. The primary data of the present research were obtained from questionnaires and interviews with some respondents. While secondary data were gained through the records and publications of related instances. Findings: The research concluded that the empowerment of Green IT provides a significant role in creativity and innovation as well as social capital, and at the same time it also supplies a significant role in innovation. Research limitations/implications:. This study is proposed to fill the research gap and at the same time to emphasize the importance of the creative empowerment of SMEs in Indonesia in adopting Green IT and that they are not only ready to make use of Green IT. Green IT empowerment and social capital in the creative SMEs play an important function ingenerating of creativity and innovation in the Yogyakarta’s creative SMEs. Creative industries which capitalize creative ideas and skills are expected to positively contribute to support the national economy. Practical implications: Creative SMEs grow and develop rapidly here and form clusters of creative industries in accordance with the resources of each cluster. Originality/value: This paper is a first attempt to overlook the significant role of green IT empowerment in SMEs’ rapid development in Yogyakarta, a growing province in economic sector in Indonesia. The result of the study is expected to lead other similar research which in the future will craft out the role of economic development and the use of environmental friendly material of production. © 2015, Universitat Politecnica de Catalunya. All rights reserved.
Indrianti N.,University of Pembangunan Nasional Veteran, Yogyakarta |
Biru N.B.,University of Pembangunan Nasional Veteran, Yogyakarta |
Wibawa T.,University of Pembangunan Nasional Veteran, Yogyakarta
Procedia CIRP | Year: 2016
This study deals with noise problem at the Indonesian teak wood furniture manufacturing company called PT Jawa Furni Lestari. The noise is generated by air compressor which is used for dyeing and spraying processes in the assembly area. The highest noise intensity indicates the value of 106.28 dB, which passes the threshold value i.e. 85 dB. The aim of this study is to reduce the noise level by constructing noise barrier. We used Pahl and Beitz approach for the barrier development process and modified idle space under the stairs in the assembly area. Consequently the compressor must be relocated from its present location. The result of the study shows that the construction of the barrier could reduce noise by 32.29 dB. In addition to reducing noise due to barrier construction, compressor relocation provides larger area for production activities. The evaluation result shows that the operators in the assembly area are very satisfied with the condition after the barrier is constructed. © 2016 The Authors. Published by Elsevier B.V.
Yatini,University of Pembangunan Nasional Veteran, Yogyakarta
AIP Conference Proceedings | Year: 2013
The relationship between metal mineral content and induced polarization response is not well known. Mathematical and physical modeling in laboratory scale was applied to find out those relationship. Their relationship was obtained by curve mathching. The physical modeling data quality was very importand in obtaining the relationship, therefore accurate and precise measurements are needed. Physical modeling data quality depend on the type of electrode, measurement techniques and equipment. Therefore, it is important to know the characteristics of the utilized potential electrode materials. The results show that porouspot is the most excellent potential electrodes used for TDIP physical modeling. The obtained resistivity and chargeability of the TDIP response of the porouspot electrodes and copper electrodes are 16.11 Ohm-m and 0.015 mSec, and 16 Ohm-m and 0.36 mSec, respectively. It is concluded that the groundwater can be used in homogeneous isotropic medium approach and also it is a good method for host medium in physical modeling. © 2013 AIP Publishing LLC.
Suranto A.M.,Sejong University |
Suranto A.M.,University of Pembangunan Nasional Veteran, Yogyakarta |
Permadi A.K.,Bandung Institute of Technology |
Bae W.,Sejong University
International Journal of Oil, Gas and Coal Technology | Year: 2016
Cyclic steam stimulation (CSS) has succeeded in recovering bitumen and heavy oil. However, after the fifth cycle, the process is no longer effective as indicated by the increasing cumulative steam-oil ratio (cSOR). This paper proposes an improvement to the CSS performance by modifying the completion design. The perforation interval is divided into two parts: upper section (for injection) and lower section (for production). In such design, the injected steam would condense due to heat loss. The steam would then flow to the lower section because of gravity force and the oil starts to produce. The injection-production cycle is managed by an interval control valve (ICV). Simulation results show that the proposed design would reduce the cSOR up to 30% and increase the cumulative oil production by 3.5 times. It is also revealed that the longer the distance between the injection and production sections, the better the steam efficiency. © 2016 Inderscience Enterprises Ltd.